Question: Simplify the following expression: $k = \dfrac{4}{7a} + \dfrac{3}{4a}$
In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $7a$ and $4a$ $\lcm(7a, 4a) = 28a$ $ k = \dfrac{4}{4} \cdot \dfrac{4}{7a} + \dfrac{7}{7} \cdot \dfrac{3}{4a} $ $k = \dfrac{16}{28a} + \dfrac{21}{28a}$ $k = \dfrac{16 +21}{28a}$ $k = \dfrac{37}{28a}$